Dreaming and the default network: A review,synthesis, and counterintuitive research proposal

This article argues that the default network, augmented by secondary visual and sensorimotor cortices, is the likely neural correlate of dreaming. This hypothesis is based on a synthesis of work on dream content, the findings on the contents and neural correlates of mind-wandering, and the results from EEG and neuroimaging studies of REM sleep. Relying on studies in the 1970s that serendipitously discovered episodes of dreaming during waking mind-wandering, this article presents the seemingly counterintuitive hypothesis that the neural correlates for dreaming could be further specified in the process of carrying out EEG/fMRI studies of mind-wandering and default network activity. This hypothesis could be tested by asking participants for experiential reports during moments of differentially high levels of default network activation, as indicated by mixed EEG/fMRI criteria. Evidence from earlier EEG/fMRI studies of mind-wandering and from laboratory studies of dreaming during the sleep-onset process is used to support the argument.     

Dreams,emotions, and social sharing of dreams

Current life emotional experiences have been demonstrated to elicit a process called social sharing of emotion, consisting of repetitive talking about these experiences in conversations with relevant others. Like many diurnal experiences, dreams are generally loaded with emotional elements, and empirical evidence has suggested that individuals share their dreams with others mainly belonging to the circle of intimates. The present study examined whether the intensity of the emotion experienced in a dream predicts the extent to which this dream is socially shared. The prediction was tested independently for positively valenced and negatively valenced dreams, on two samples of respondents, i.e., Belgians and Italians. Other potential predictors of sharing were considered, including a number of cognitive appraisals and cognitive consequences of emotion. Results confirmed that emotion intensity is the main predictor of social sharing for both negative and positive dreams. In addition, the analysis of dream contents accounted for a high level of emotional intensity associated with respondents’ dreaming. Implications for theory and functions fulfilled by emotion with regard to social interactions are discussed.     

Concern-induced negative affect is associated with the occurrence and content of mind-wandering

Previous research has shown that the content and frequency of mind-wandering episodes—the occurrence of thoughts that are both stimulus-independent and task-unrelated—are closely related to an individual’s future-related concerns. Whether this relationship is shaped by the affective changes that are usually associated with future-related concerns still remains unclear, however. In this study, we induced the anticipation of a negatively valenced event and examined whether the ensuing affective changes were related to the occurrence and content of mind-wandering during an unrelated attentional task. We found that the increase in negative affect following concern induction predicted the general frequency of mind-wandering episodes. Furthermore, mind-wandering episodes specifically directed at the induced concern were related to a lower decrease in negative affect during the attentional task. These results suggest that the negative emotional impact of future-related concerns is an important factor to be taken into consideration for the subsequent occurrence of mind-wandering episodes, which might in turn be involved in the maintenance of negative affect over time.     

Dreaming and waking: similarities and differences revisited

Dreaming is often characterized as lacking high-order cognitive (HOC) skills. In two studies, we test the alternative hypothesis that the dreaming mind is highly similar to the waking mind. Multiple experience samples were obtained from late-night REM sleep and waking, following a systematic protocol described in Kahan (2001). Results indicated that reported dreaming and waking experiences are surprisingly similar in their cognitive and sensory qualities. Concurrently, ratings of dreaming and waking experiences were markedly different on questions of general reality orientation and logical organization (e.g., the bizarreness or typicality of the events, actions, and locations). Consistent with other recent studies (e.g., [Bulkeley and Kahan, 2008] and [Kozmová and Wolman, 2006] ), experiences sampled from dreaming and waking were more similar with respect to their process features than with respect to their structural features.     

Continuity between waking activities and dream activities

Empirical studies largely support the continuity hypothesis of dreaming. Despite of previous research efforts, the exact formulation of the continuity hypothesis remains vague. The present paper focuses on two aspects: (1) the differential incorporation rate of different waking-life activities and (2) the magnitude of which interindividual differences in waking-life activities are reflected in corresponding differences in dream content. Using a correlational design, a positive, non-zero correlation coefficient will support the continuity hypothesis. Although many researchers stress the importance of emotional involvement on the incorporation rate of waking-life experiences into dreams, formulated the hypothesis that highly focused cognitive processes such as reading, writing, etc. are rarely found in dreams due to the cholinergic activation of the brain during dreaming. The present findings based on dream diaries and the exact measurement of waking activities replicated two recent questionnaire studies. These findings indicate that it will be necessary to specify the continuity hypothesis more fully and include factors (e.g., type of waking-life experience, emotional involvement) which modulate the incorporation rate of waking-life experiences into dreams. Whether the cholinergic state of the brain during REM sleep or other alterations of brain physiology (e.g., down-regulation of the dorsolateral prefrontal cortex) are the underlying factors of the rare occurrence of highly focused cognitive processes in dreaming remains an open question. Although continuity between waking life and dreaming has been demonstrated, i.e., interindividual differences in the amount of time spent with specific waking-life activities are reflected in dream content, methodological issues (averaging over a two-week period, small number of dreams) have limited the capacity for detecting substantial relationships in all areas. Nevertheless, it might be concluded that the continuity hypothesis in its present general form is not valid and should be elaborated and tested in a more specific way.     

Waking and dreaming: related but structurally independent. Dream reports of congenitally paraplegic and deaf-mute persons

Models of dream analysis either assume a continuum of waking and dreaming or the existence of two dissociated realities. Both approaches rely on different methodology. Whereas continuity models are based on content analysis, discontinuity models use a structural approach. In our study, we applied both methods to test specific hypotheses about continuity or discontinuity. We contrasted dream reports of congenitally deaf-mute and congenitally paraplegic individuals with those of non-handicapped controls. Continuity theory would predict that either the deficit itself or compensatory experiences would surface in the dream narrative. We found that dream form and content of sensorially limited persons was indifferent from those of non-handicapped controls. Surprisingly, perceptual representations, even of modalities not experienced during waking, were quite common in the dream reports of our handicapped subjects. Results are discussed with respect to feedforward mechanisms and protoconsciousness theory of dreaming.     

Partial memory reinstatement while (lucid) dreaming to change the dream environment

Lucid dreams often coincide with having control over dream events in real-time, although the limitations of dream control are not completely understood. The current study probed the ability of lucid dreamers to reinstate waking scene memories while dreaming. After brief exposure to an experimental scene, participants were asked to reinstate the scene while lucid dreaming (i.e., change dream scenery to match real-world scene). Qualitative analysis revealed that successful dream scene reinstatements were overwhelmingly inaccurate with respect to the original experimental scene. Importantly, reinstatement inaccuracies held even when the dreamer was aware of them during the dream, suggesting a dissociation between memory access while dreaming and dream imagery. The ability to change the environment of a dream speaks to the high amount of lucid dream control, yet the inaccuracies speak to a lack of detailed control. Reinstating context during lucid sleep offers an experimental method to investigate sleep, dreams, and memory.     

Cultural Differences in Preference for Entertainment Messages That Induce Mixed Responses of Joy and Sorrow

Two cross‐cultural studies were conducted to explore how affective states from viewing favorite entertainment messages vary as a function of culture. Koreans were more likely than U.S. Americans to prefer entertainment messages that induce conflicting responses (e.g., feeling positive and negative, laughing and crying). Furthermore, this cultural difference was larger for positively valenced (i.e., comedy) than for negatively valenced message (i.e., sad films). Naïve dialecticism held by East Asians that treats these contradictory responses as balance, harmony, and moderation was introduced as a plausible explanatory mechanism.     

Dreams are more negative than real life: Implications for the function of dreaming

Dream content studies have revealed that dream experiences are negatively biased; negative dream contents are more frequent than corresponding positive dream contents. It is unclear, however, whether the bias is real or due to biased sampling, i.e., selective memory for intense negative emotions. The threat simulation theory (TST) claims that the negativity bias is real and reflects the evolved biological function of dreaming. In the present study, we tested the hypothesis of the TST that threatening events are overrepresented in dreams, i.e., more frequent and more severe in dreams than in real life. To control for biased sampling, we used as a baseline the corresponding negative events in real life rather than the corresponding positive events in dreams. We collected dream reports (N=419) and daily event logs (N=490) from 39 university students during a two-week period, and interviewed them about real threat experiences retrievable from autobiographical memory (N=714). Threat experiences proved to be much more frequent and severe in dreams than in real life, and Current Dream Threats more closely resembled Past than Current Real Threats. We conclude that the TST's predictions hold, and that the negativity bias is real.     

Developmental relationships and managerial promotability in organizations: A multisource study

Managers are now focusing on developmental relationships by providing career-related mentoring to their direct reports, but research is lacking in showing whether such mentoring is in fact related to outcomes that benefit the manager. This study investigates whether self- and direct report ratings of the extent to which focal-managers provide career-related mentoring are associated with perceptions of their promotability as perceived by their bosses (n = 1623) and peers (n = 1597). Results of hierarchical regression indicated that both self- and direct report ratings of focal-managers' career-related mentoring were significant and positively related to boss and peer ratings of focal-managers' promotability. Within a self-other rating agreement framework, results of polynomial regression indicated that higher ratings of career-related mentoring by focal-managers and their direct reports were positively related to both boss and peer ratings of focal-managers' promotability. Furthermore, underrating (i.e., when self-ratings are lower than direct report ratings) was more positively related to promotability than overrating (i.e., when self-ratings are higher than direct report ratings).     

Another look at dreaming: disentangling Freud's primary and secondary process theories

The Interpretation of Dreams contains Freud's first and most complete articulation of the primary and secondary mental processes that serve as a framework for the workings of mind, conscious and unconscious. While it is generally believed that Freud proposed a single theory of dreaming, based on the primary process, a number of ambiguities, inconsistencies, and contradictions reflect an incomplete differentiation of the parts played by the two mental processes in dreaming. It is proposed that two radically different hypotheses about dreaming are embedded in Freud's work. The one implicit in classical dream interpretation is based on the assumption that dreams, like waking language, are representational, and are made up of symbols connected to latent unconscious thoughts. Whereas the symbols that constitute waking language are largely verbal and only partly unconscious, those that constitute dreams are presumably more thoroughly disguised and represented as arcane hallucinated hieroglyphs. From this perspective, both the language of the dream and that of waking life are secondary process manifestations. Interpretation of the dream using the secondary process model involves the assumption of a linear two-way "road" connecting manifest and latent aspects, which in one direction involves the work of dream construction and in the other permits the associative process of decoding and interpretation. Freud's more revolutionary hypothesis, whose implications he did not fully elaborate, is that dreams are the expression of a primary mental process that differs qualitatively from waking thought and hence are incomprehensible through a secondary process model. This seems more adequately to account for what is now known about dreaming, and is more consistent with the way dream interpretation is ordinarily conducted in clinical practice. Recognition that dreams are qualitatively distinctive expressions of mind may help to restore dreaming to its privileged position as a unique source of mental status information.     

The Religious Content of Dreams: A New Scientific Foundation

Dream content is meaningfully related to waking life religiosity, so much so that reading a person’s dream reports “blindly,” without any other personal information or associations from the dreamer, can reveal with surprising accuracy his or her basic waking attitude toward religion and spirituality. Two long-term dream journals are analyzed in this manner, and the results demonstrate that dream content is an accurate reflection of a person’s religious beliefs, practices, and experiences. The significance of this for pastoral psychologists lies not in specific new techniques of dream interpretation but more fundamentally in supporting the practice of paying attention to dreams in the first place. The goal of the article is to build a bridge between pastoral psychological interest in dreams and the latest findings in the scientific study of dreaming. Contrary to the assumption that religion and science inevitably conflict with each other, dreaming offers an area of potential religion–science convergence.     

How to integrate dreaming into a general theory of consciousness--a critical review of existing positions and suggestions for future research

In this paper, we address the different ways in which dream research can contribute to interdisciplinary consciousness research. As a second global state of consciousness aside from wakefulness, dreaming is an important contrast condition for theories of waking consciousness. However, programmatic suggestions for integrating dreaming into broader theories of consciousness, for instance by regarding dreams as a model system of standard or pathological wake states, have not yielded straightforward results. We review existing proposals for using dreaming as a model system, taking into account concerns about the concept of modeling and the adequacy and practical feasibility of dreaming as a model system. We conclude that existing modeling approaches are premature and rely on controversial background assumptions. Instead, we suggest that contrastive analysis of dreaming and wakefulness presents a more promising strategy for integrating dreaming into a broader research context and solving many of the problems involved in the modeling approach.     

I know how you felt last night,or do I? Self- and external ratings of emotions in REM sleep dreams

We investigated whether inconsistencies in previous studies regarding emotional experiences in dreams derive from whether dream emotions are self-rated or externally evaluated. Seventeen subjects were monitored with polysomnography in the sleep laboratory and awakened from every rapid eye movement (REM) sleep stage 5 min after the onset of the stage. Upon awakening, participants gave an oral dream report and rated their dream emotions using the modified Differential Emotions Scale, whereas external judges rated the participants’ emotions expressed in the dream reports, using the same scale. The two approaches produced diverging results. Self-ratings, as compared to external ratings, resulted in greater estimates of (a) emotional dreams; (b) positively valenced dreams; (c) positive and negative emotions per dream; and (d) various discrete emotions represented in dreams. The results suggest that this is mostly due to the underrepresentation of positive emotions in dream reports. Possible reasons for this discrepancy are discussed.     

Visual-Verbal Self/Other-Referential Processing Task: Direct vs. indirect assessment, valence, and experiential correlates

This study evaluated a new methodology for assessing valenced Self-Referential Processing (SRP) in comparison with Other-Referential Processing (ORP). Participants viewed pictures of themselves during certain trials and same-gender strangers during others, intermixed between valenced words. Participants internally-rehearsed the words “I am” or “He/she is” when presented with the respective pictures and read the valenced words, thereby associating the self/other with positivity/negativity on different trials. Participants self-monitored their affective response, and their degree of attention and/or rate of internal speech/reading speed was measured indirectly via button-press response time (RT). Results in 91 young adults demonstrated a self-positivity bias in survey ratings, stronger affective responses during SRP than ORP, slower RT during SRP than ORP, and slower RT during positive than negative valence. Difference scores between SRP of negative- vs. positive-valence trials, and between SRP vs. ORP of negative-valence trials, were correlated among survey ratings, affective responses, and RT. Finally, content analyses of phenomenological reports showed that task conditions differentially provoked a number of socioemotional experiences during both SRP and ORP (e.g., jealousy-envy, sympathy-pity, good will/pride). We discuss potential applications of the task in the study of personality and individual differences.     

Sleep fragmentation and lucid dreaming

Lucid dreaming—the phenomenon of experiencing waking levels of self-reflection within one’s dreams—is associated with more wake-like levels of neural activation in prefrontal brain regions. In addition, alternating periods of wakefulness and sleep might increase the likelihood of experiencing a lucid dream. Here we investigate the association between sleep fragmentation and lucid dreaming, with a multi-centre study encompassing four different investigations into subjective and objective measures of sleep fragmentation, nocturnal awakenings, sleep quality and polyphasic sleep schedules. Results across these four studies provide a more nuanced picture into the purported connection between sleep fragmentation and lucid dreaming: While self-assessed numbers of awakenings, polyphasic sleep and physiologically validated wake-REM sleep transitions were associated with lucid dreaming, neither self-assessed sleep quality, nor physiologically validated numbers of awakenings were. We discuss these results, and their underlying neural mechanisms, within the general question of whether sleep fragmentation and lucid dreaming share a causal link.     

The immersive spatiotemporal hallucination model of dreaming

The paper proposes a minimal definition of dreaming in terms of immersive spatiotemporal hallucination (ISTH) occurring in sleep or during sleep–wake transitions and under the assumption of reportability. I take these conditions to be both necessary and sufficient for dreaming to arise. While empirical research results may, in the future, allow for an extension of the concept of dreaming beyond sleep and possibly even independently of reportability, ISTH is part of any possible extension of this definition and thus is a constitutive condition of dreaming. I also argue that the proposed ISTH model of dreaming, in conjunction with considerations on the epistemic relationship between dreaming and dream reports, raises important questions about the extent to which dreams typically involve a detailed body representation—an assumption that plays an important role in philosophical work on dreaming. As a commonly accepted definition of dreaming is lacking in current dream research, the ISTH model, which integrates conceptual analysis and epistemological considerations with results from empirical research, is an important contribution to this field. By linking dreaming to felt presence, full-body illusions, and autoscopic phenomena such as out-of-body experiences in wakefulness and in the hypnagogic state, the ISTH model of dreaming also helps integrate dream research, both theoretically and experimentally, with the study of other altered states of consciousness involving hallucinations. It makes straightforward and investigable predictions by claiming that all of these experiences have amodal spatiotemporal hallucinations as their common denominator. Finally, it is theoretically relevant for the philosophical discussion on minimal phenomenal selfhood.     

Flow and Happiness in Later Life: An Investigation into the Role of Daily and Weekly Flow Experiences

Fifty-four older adults ranging in age from 70 to 86 years old (M = 77.54) reported daily levels of positive and negative affect, life satisfaction and daily activities for seven consecutive days. Hierarchical linear modeling (HLM) was used to investigate inter- and intra-individual effects of flow experiences on affect. Higher quality of flow was positively associated with high arousal positive affect (i.e., feeling peppy, enthusiastic, happy), negatively associated with low arousal negative affect (i.e., feeling sad and disappointed), and positively associated with life satisfaction. However, more frequent flow experiences throughout the week predicted lower average levels of positive affect and life satisfaction. Overall, the results demonstrate that flow is linked to the affective experiences of older adults, and that an individual’s overall propensity to experience flow may be influential beyond the immediate effects of a given flow experience.     

Emotions in Diary Dreams

Even though various investigations found a preponderance of negative emotions in dreams, the conclusion that human dream life is, in general, negatively toned is limited by several methodological issues. The present study made use of three different approaches to measure dream emotions: dream intensity rated by the dreamer, intensity rated by a judge, and scoring of explicitly mentioned emotions (Hall & Van de Castle, 1966). Results indicate that only in the case of external raters' estimates do negative emotions outweigh the positive ones; but in the case of self-ratings (i.e., those made by the dreamer himself/herself), the ratio was balanced. Analyses showed that this is mainly due to the underestimation of positive emotions in the external ratings. Additionally, a positive correlation was found between the intensity of dream emotions and dream recall frequency, whereas gender differences were nonsignificant as regards the emotional tone of diary dreams.     

My Recency,Our Primacy: How Social Connection Influences Evaluations of Sequences

Individuals have many life experiences (e.g., work and vacations) that consist of a series of interconnected episodes (i.e., temporal sequences). Assessments of such experiences are integral to daily life in that they facilitate future planning and behaviors for individuals. Therefore, these experiences often culminate in evaluations of their global affect. Past work has shown that retrospective, affective evaluations of these sequences generally exhibit an “end effect,” whereby a sequence's end intensity—but not its start intensity—is disproportionately weighted. Yet, researchers have largely investigated experiences that occur alone. In contrast, many real‐world experiences vary in their extent of social connection to others (e.g., working in an office with others versus alone in a cubicle). The present work fills this gap by showing the moderating role of social connection on how episodes are weighted in global affective ratings. Five studies involving two autobiographical experiences spanning several days each (workweek and spring break) and two brief simulated experiences show that high social connection leads to greater (lesser) weighting of the first (last) episode. To our knowledge, we are the first to demonstrate that these effects persist across different forms of social connection (i.e., interpersonal interaction versus semantic priming tasks) and are supported regardless of whether social connection occurs at encoding or retrieval of an experience. Copyright © 2015 John Wiley & Sons, Ltd.